Snoot and Fin partition numbers into tens and units to help count plants in their garden.
NARRATOR: Hello you two.
What was that thing?
SNOOT: (ALIEN LANGUAGE)
NARRATOR: A grubble mulcher?
It certainly made a meal of the vegetable planters.
What's the damage, Snoot?
SNOOT: (ALIEN LANGUAGE)
NARRATOR: Oh no!
That mulcher nearly ate up all of your purple sprouting cattersnips.
At least it left the grokklechokes.
It looks like you've got some replanting to do鈥
SNOOT: (ALIEN LANGUAGE)
NARRATOR: How many cattersnips do you need to replant?
Let's take a look.
The grubble mulcher ate 17 cattersnips from one planter, and 14 from the other planter.
What's 14 add 17?
SNOOT: Er鈥 Uh鈥
NARRATOR: Yes, that is quite a hard sum.
It might be easier if we separate the 17 into a 10 and a 7, and the 14 into a 10 and a 4.
That gives us a 10, a 10, a 7 and a 4.
Let's start by adding the units.
4 add 7 equals 11, which is a 10 with a 1 left over.
That means we've now got three 10s and 1 to add up.
So that's 10, 20, 30, add 1, equals 31 all together.
BOTH: Aha!
NARRATOR: Oh no鈥
It looks like you'll have to replant the grokklechokes as well.
(GRUBBLE MULCHER BREAKS WIND)
How can I add two-digit numbers?
Adding two digit numbers can be tricky.
You can make it easier by splitting each number into tens and units.
Splitting numbers apart like this is called partitioning.
Example
21 + 45 = ?
21 is the same as 20 + 1
45 is the same as 40 + 5
So 21 + 45 can be written as 20 + 1 + 40 + 5
Try adding the tens first 20 + 40 = 60
Then add the units 1 + 5 = 6
Then add these together 60 + 6 = 66
Was that easier?
More on Number and number processes
Find out more by working through a topic
- count20 of 25
- count21 of 25
- count22 of 25
- count23 of 25
